diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c
index 0a2a87208b1..c47ce907572 100644
--- a/fs/xfs/xfs_alloc.c
+++ b/fs/xfs/xfs_alloc.c
@@ -380,21 +380,20 @@ xfs_alloc_fixup_trees(
 			return error;
 		XFS_WANT_CORRUPTED_RETURN(i == 1);
 	}
-#ifdef DEBUG
-	{
-		xfs_alloc_block_t	*bnoblock;
-		xfs_alloc_block_t	*cntblock;
 
-		if (bno_cur->bc_nlevels == 1 &&
-		    cnt_cur->bc_nlevels == 1) {
-			bnoblock = XFS_BUF_TO_ALLOC_BLOCK(bno_cur->bc_bufs[0]);
-			cntblock = XFS_BUF_TO_ALLOC_BLOCK(cnt_cur->bc_bufs[0]);
-			XFS_WANT_CORRUPTED_RETURN(
-				be16_to_cpu(bnoblock->bb_numrecs) ==
-				be16_to_cpu(cntblock->bb_numrecs));
-		}
+#ifdef DEBUG
+	if (bno_cur->bc_nlevels == 1 && cnt_cur->bc_nlevels == 1) {
+		struct xfs_btree_block	*bnoblock;
+		struct xfs_btree_block	*cntblock;
+
+		bnoblock = XFS_BUF_TO_BLOCK(bno_cur->bc_bufs[0]);
+		cntblock = XFS_BUF_TO_BLOCK(cnt_cur->bc_bufs[0]);
+
+		XFS_WANT_CORRUPTED_RETURN(
+			bnoblock->bb_numrecs == cntblock->bb_numrecs);
 	}
 #endif
+
 	/*
 	 * Deal with all four cases: the allocated record is contained
 	 * within the freespace record, so we can have new freespace
diff --git a/fs/xfs/xfs_alloc_btree.c b/fs/xfs/xfs_alloc_btree.c
index 72c083f62a9..733cb75a8c5 100644
--- a/fs/xfs/xfs_alloc_btree.c
+++ b/fs/xfs/xfs_alloc_btree.c
@@ -490,7 +490,7 @@ xfs_allocbt_maxrecs(
 	int			blocklen,
 	int			leaf)
 {
-	blocklen -= sizeof(struct xfs_btree_sblock);
+	blocklen -= XFS_ALLOC_BLOCK_LEN(mp);
 
 	if (leaf)
 		return blocklen / sizeof(xfs_alloc_rec_t);
diff --git a/fs/xfs/xfs_alloc_btree.h b/fs/xfs/xfs_alloc_btree.h
index 579f9c7e087..a6caa0022c9 100644
--- a/fs/xfs/xfs_alloc_btree.h
+++ b/fs/xfs/xfs_alloc_btree.h
@@ -24,7 +24,6 @@
 
 struct xfs_buf;
 struct xfs_btree_cur;
-struct xfs_btree_sblock;
 struct xfs_mount;
 
 /*
@@ -50,10 +49,6 @@ typedef struct xfs_alloc_rec_incore {
 
 /* btree pointer type */
 typedef __be32 xfs_alloc_ptr_t;
-/* btree block header type */
-typedef	struct xfs_btree_sblock xfs_alloc_block_t;
-
-#define	XFS_BUF_TO_ALLOC_BLOCK(bp)	((xfs_alloc_block_t *)XFS_BUF_PTR(bp))
 
 /*
  * Minimum and maximum blocksize and sectorsize.
@@ -76,6 +71,13 @@ typedef	struct xfs_btree_sblock xfs_alloc_block_t;
 #define	XFS_BNO_BLOCK(mp)	((xfs_agblock_t)(XFS_AGFL_BLOCK(mp) + 1))
 #define	XFS_CNT_BLOCK(mp)	((xfs_agblock_t)(XFS_BNO_BLOCK(mp) + 1))
 
+/*
+ * Btree block header size depends on a superblock flag.
+ *
+ * (not quite yet, but soon)
+ */
+#define XFS_ALLOC_BLOCK_LEN(mp)	XFS_BTREE_SBLOCK_LEN
+
 /*
  * Record, key, and pointer address macros for btree blocks.
  *
@@ -84,19 +86,19 @@ typedef	struct xfs_btree_sblock xfs_alloc_block_t;
 #define XFS_ALLOC_REC_ADDR(mp, block, index) \
 	((xfs_alloc_rec_t *) \
 		((char *)(block) + \
-		 sizeof(struct xfs_btree_sblock) + \
+		 XFS_ALLOC_BLOCK_LEN(mp) + \
 		 (((index) - 1) * sizeof(xfs_alloc_rec_t))))
 
 #define XFS_ALLOC_KEY_ADDR(mp, block, index) \
 	((xfs_alloc_key_t *) \
 		((char *)(block) + \
-		 sizeof(struct xfs_btree_sblock) + \
+		 XFS_ALLOC_BLOCK_LEN(mp) + \
 		 ((index) - 1) * sizeof(xfs_alloc_key_t)))
 
 #define XFS_ALLOC_PTR_ADDR(mp, block, index, maxrecs) \
 	((xfs_alloc_ptr_t *) \
 		((char *)(block) + \
-		 sizeof(struct xfs_btree_sblock) + \
+		 XFS_ALLOC_BLOCK_LEN(mp) + \
 		 (maxrecs) * sizeof(xfs_alloc_key_t) + \
 		 ((index) - 1) * sizeof(xfs_alloc_ptr_t)))
 
diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
index 3dab937d4b8..7796a0c140e 100644
--- a/fs/xfs/xfs_bmap.c
+++ b/fs/xfs/xfs_bmap.c
@@ -394,7 +394,7 @@ xfs_bmap_count_leaves(
 STATIC void
 xfs_bmap_disk_count_leaves(
 	struct xfs_mount	*mp,
-	xfs_bmbt_block_t	*block,
+	struct xfs_btree_block	*block,
 	int			numrecs,
 	int			*count);
 
@@ -3042,14 +3042,14 @@ xfs_bmap_btree_to_extents(
 	int			whichfork)  /* data or attr fork */
 {
 	/* REFERENCED */
-	xfs_bmbt_block_t	*cblock;/* child btree block */
+	struct xfs_btree_block	*cblock;/* child btree block */
 	xfs_fsblock_t		cbno;	/* child block number */
 	xfs_buf_t		*cbp;	/* child block's buffer */
 	int			error;	/* error return value */
 	xfs_ifork_t		*ifp;	/* inode fork data */
 	xfs_mount_t		*mp;	/* mount point structure */
 	__be64			*pp;	/* ptr to block address */
-	xfs_bmbt_block_t	*rblock;/* root btree block */
+	struct xfs_btree_block	*rblock;/* root btree block */
 
 	mp = ip->i_mount;
 	ifp = XFS_IFORK_PTR(ip, whichfork);
@@ -3069,8 +3069,8 @@ xfs_bmap_btree_to_extents(
 	if ((error = xfs_btree_read_bufl(mp, tp, cbno, 0, &cbp,
 			XFS_BMAP_BTREE_REF)))
 		return error;
-	cblock = XFS_BUF_TO_BMBT_BLOCK(cbp);
-	if ((error = xfs_btree_check_lblock(cur, cblock, 0, cbp)))
+	cblock = XFS_BUF_TO_BLOCK(cbp);
+	if ((error = xfs_btree_check_block(cur, cblock, 0, cbp)))
 		return error;
 	xfs_bmap_add_free(cbno, 1, cur->bc_private.b.flist, mp);
 	ip->i_d.di_nblocks--;
@@ -3450,11 +3450,11 @@ xfs_bmap_extents_to_btree(
 	int			*logflagsp,	/* inode logging flags */
 	int			whichfork)	/* data or attr fork */
 {
-	xfs_bmbt_block_t	*ablock;	/* allocated (child) bt block */
+	struct xfs_btree_block	*ablock;	/* allocated (child) bt block */
 	xfs_buf_t		*abp;		/* buffer for ablock */
 	xfs_alloc_arg_t		args;		/* allocation arguments */
 	xfs_bmbt_rec_t		*arp;		/* child record pointer */
-	xfs_bmbt_block_t	*block;		/* btree root block */
+	struct xfs_btree_block	*block;		/* btree root block */
 	xfs_btree_cur_t		*cur;		/* bmap btree cursor */
 	xfs_bmbt_rec_host_t	*ep;		/* extent record pointer */
 	int			error;		/* error return value */
@@ -3474,6 +3474,7 @@ xfs_bmap_extents_to_btree(
 	 */
 	xfs_iroot_realloc(ip, 1, whichfork);
 	ifp->if_flags |= XFS_IFBROOT;
+
 	/*
 	 * Fill in the root.
 	 */
@@ -3481,8 +3482,9 @@ xfs_bmap_extents_to_btree(
 	block->bb_magic = cpu_to_be32(XFS_BMAP_MAGIC);
 	block->bb_level = cpu_to_be16(1);
 	block->bb_numrecs = cpu_to_be16(1);
-	block->bb_leftsib = cpu_to_be64(NULLDFSBNO);
-	block->bb_rightsib = cpu_to_be64(NULLDFSBNO);
+	block->bb_u.l.bb_leftsib = cpu_to_be64(NULLDFSBNO);
+	block->bb_u.l.bb_rightsib = cpu_to_be64(NULLDFSBNO);
+
 	/*
 	 * Need a cursor.  Can't allocate until bb_level is filled in.
 	 */
@@ -3534,11 +3536,11 @@ xfs_bmap_extents_to_btree(
 	/*
 	 * Fill in the child block.
 	 */
-	ablock = XFS_BUF_TO_BMBT_BLOCK(abp);
+	ablock = XFS_BUF_TO_BLOCK(abp);
 	ablock->bb_magic = cpu_to_be32(XFS_BMAP_MAGIC);
 	ablock->bb_level = 0;
-	ablock->bb_leftsib = cpu_to_be64(NULLDFSBNO);
-	ablock->bb_rightsib = cpu_to_be64(NULLDFSBNO);
+	ablock->bb_u.l.bb_leftsib = cpu_to_be64(NULLDFSBNO);
+	ablock->bb_u.l.bb_rightsib = cpu_to_be64(NULLDFSBNO);
 	arp = XFS_BMBT_REC_ADDR(mp, ablock, 1);
 	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
 	for (cnt = i = 0; i < nextents; i++) {
@@ -3550,7 +3552,8 @@ xfs_bmap_extents_to_btree(
 		}
 	}
 	ASSERT(cnt == XFS_IFORK_NEXTENTS(ip, whichfork));
-	ablock->bb_numrecs = cpu_to_be16(cnt);
+	xfs_btree_set_numrecs(ablock, cnt);
+
 	/*
 	 * Fill in the root key and pointer.
 	 */
@@ -4533,7 +4536,7 @@ xfs_bmap_read_extents(
 	xfs_inode_t		*ip,	/* incore inode */
 	int			whichfork) /* data or attr fork */
 {
-	xfs_bmbt_block_t	*block;	/* current btree block */
+	struct xfs_btree_block	*block;	/* current btree block */
 	xfs_fsblock_t		bno;	/* block # of "block" */
 	xfs_buf_t		*bp;	/* buffer for "block" */
 	int			error;	/* error return value */
@@ -4570,7 +4573,7 @@ xfs_bmap_read_extents(
 		if ((error = xfs_btree_read_bufl(mp, tp, bno, 0, &bp,
 				XFS_BMAP_BTREE_REF)))
 			return error;
-		block = XFS_BUF_TO_BMBT_BLOCK(bp);
+		block = XFS_BUF_TO_BLOCK(bp);
 		XFS_WANT_CORRUPTED_GOTO(
 			XFS_BMAP_SANITY_CHECK(mp, block, level),
 			error0);
@@ -4596,7 +4599,7 @@ xfs_bmap_read_extents(
 		xfs_extnum_t	start;
 
 
-		num_recs = be16_to_cpu(block->bb_numrecs);
+		num_recs = xfs_btree_get_numrecs(block);
 		if (unlikely(i + num_recs > room)) {
 			ASSERT(i + num_recs <= room);
 			xfs_fs_repair_cmn_err(CE_WARN, ip->i_mount,
@@ -4613,7 +4616,7 @@ xfs_bmap_read_extents(
 		/*
 		 * Read-ahead the next leaf block, if any.
 		 */
-		nextbno = be64_to_cpu(block->bb_rightsib);
+		nextbno = be64_to_cpu(block->bb_u.l.bb_rightsib);
 		if (nextbno != NULLFSBLOCK)
 			xfs_btree_reada_bufl(mp, nextbno, 1);
 		/*
@@ -4650,7 +4653,7 @@ xfs_bmap_read_extents(
 		if ((error = xfs_btree_read_bufl(mp, tp, bno, 0, &bp,
 				XFS_BMAP_BTREE_REF)))
 			return error;
-		block = XFS_BUF_TO_BMBT_BLOCK(bp);
+		block = XFS_BUF_TO_BLOCK(bp);
 	}
 	ASSERT(i == (ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t)));
 	ASSERT(i == XFS_IFORK_NEXTENTS(ip, whichfork));
@@ -6175,7 +6178,7 @@ xfs_bmap_get_bp(
 
 void
 xfs_check_block(
-	xfs_bmbt_block_t        *block,
+	struct xfs_btree_block	*block,
 	xfs_mount_t		*mp,
 	int			root,
 	short			sz)
@@ -6187,7 +6190,7 @@ xfs_check_block(
 	ASSERT(be16_to_cpu(block->bb_level) > 0);
 
 	prevp = NULL;
-	for( i = 1; i <= be16_to_cpu(block->bb_numrecs); i++) {
+	for( i = 1; i <= xfs_btree_get_numrecs(block); i++) {
 		dmxr = mp->m_bmap_dmxr[0];
 		keyp = XFS_BMBT_KEY_ADDR(mp, block, i);
 
@@ -6232,7 +6235,7 @@ xfs_bmap_check_leaf_extents(
 	xfs_inode_t		*ip,		/* incore inode pointer */
 	int			whichfork)	/* data or attr fork */
 {
-	xfs_bmbt_block_t	*block;	/* current btree block */
+	struct xfs_btree_block	*block;	/* current btree block */
 	xfs_fsblock_t		bno;	/* block # of "block" */
 	xfs_buf_t		*bp;	/* buffer for "block" */
 	int			error;	/* error return value */
@@ -6282,7 +6285,7 @@ xfs_bmap_check_leaf_extents(
 		if (!bp && (error = xfs_btree_read_bufl(mp, NULL, bno, 0, &bp,
 				XFS_BMAP_BTREE_REF)))
 			goto error_norelse;
-		block = XFS_BUF_TO_BMBT_BLOCK(bp);
+		block = XFS_BUF_TO_BLOCK(bp);
 		XFS_WANT_CORRUPTED_GOTO(
 			XFS_BMAP_SANITY_CHECK(mp, block, level),
 			error0);
@@ -6317,13 +6320,13 @@ xfs_bmap_check_leaf_extents(
 		xfs_extnum_t	num_recs;
 
 
-		num_recs = be16_to_cpu(block->bb_numrecs);
+		num_recs = xfs_btree_get_numrecs(block);
 
 		/*
 		 * Read-ahead the next leaf block, if any.
 		 */
 
-		nextbno = be64_to_cpu(block->bb_rightsib);
+		nextbno = be64_to_cpu(block->bb_u.l.bb_rightsib);
 
 		/*
 		 * Check all the extents to make sure they are OK.
@@ -6367,7 +6370,7 @@ xfs_bmap_check_leaf_extents(
 		if (!bp && (error = xfs_btree_read_bufl(mp, NULL, bno, 0, &bp,
 				XFS_BMAP_BTREE_REF)))
 			goto error_norelse;
-		block = XFS_BUF_TO_BMBT_BLOCK(bp);
+		block = XFS_BUF_TO_BLOCK(bp);
 	}
 	if (bp_release) {
 		bp_release = 0;
@@ -6397,7 +6400,7 @@ xfs_bmap_count_blocks(
 	int			whichfork,	/* data or attr fork */
 	int			*count)		/* out: count of blocks */
 {
-	xfs_bmbt_block_t	*block;	/* current btree block */
+	struct xfs_btree_block	*block;	/* current btree block */
 	xfs_fsblock_t		bno;	/* block # of "block" */
 	xfs_ifork_t		*ifp;	/* fork structure */
 	int			level;	/* btree level, for checking */
@@ -6454,24 +6457,24 @@ xfs_bmap_count_tree(
 	__be64			*pp;
 	xfs_fsblock_t           bno = blockno;
 	xfs_fsblock_t		nextbno;
-	xfs_bmbt_block_t        *block, *nextblock;
+	struct xfs_btree_block	*block, *nextblock;
 	int			numrecs;
 
 	if ((error = xfs_btree_read_bufl(mp, tp, bno, 0, &bp, XFS_BMAP_BTREE_REF)))
 		return error;
 	*count += 1;
-	block = XFS_BUF_TO_BMBT_BLOCK(bp);
+	block = XFS_BUF_TO_BLOCK(bp);
 
 	if (--level) {
 		/* Not at node above leafs, count this level of nodes */
-		nextbno = be64_to_cpu(block->bb_rightsib);
+		nextbno = be64_to_cpu(block->bb_u.l.bb_rightsib);
 		while (nextbno != NULLFSBLOCK) {
 			if ((error = xfs_btree_read_bufl(mp, tp, nextbno,
 				0, &nbp, XFS_BMAP_BTREE_REF)))
 				return error;
 			*count += 1;
-			nextblock = XFS_BUF_TO_BMBT_BLOCK(nbp);
-			nextbno = be64_to_cpu(nextblock->bb_rightsib);
+			nextblock = XFS_BUF_TO_BLOCK(nbp);
+			nextbno = be64_to_cpu(nextblock->bb_u.l.bb_rightsib);
 			xfs_trans_brelse(tp, nbp);
 		}
 
@@ -6489,7 +6492,7 @@ xfs_bmap_count_tree(
 	} else {
 		/* count all level 1 nodes and their leaves */
 		for (;;) {
-			nextbno = be64_to_cpu(block->bb_rightsib);
+			nextbno = be64_to_cpu(block->bb_u.l.bb_rightsib);
 			numrecs = be16_to_cpu(block->bb_numrecs);
 			xfs_bmap_disk_count_leaves(mp, block, numrecs, count);
 			xfs_trans_brelse(tp, bp);
@@ -6500,7 +6503,7 @@ xfs_bmap_count_tree(
 				XFS_BMAP_BTREE_REF)))
 				return error;
 			*count += 1;
-			block = XFS_BUF_TO_BMBT_BLOCK(bp);
+			block = XFS_BUF_TO_BLOCK(bp);
 		}
 	}
 	return 0;
@@ -6531,7 +6534,7 @@ xfs_bmap_count_leaves(
 STATIC void
 xfs_bmap_disk_count_leaves(
 	struct xfs_mount	*mp,
-	xfs_bmbt_block_t	*block,
+	struct xfs_btree_block	*block,
 	int			numrecs,
 	int			*count)
 {
diff --git a/fs/xfs/xfs_bmap_btree.c b/fs/xfs/xfs_bmap_btree.c
index 11137c042c9..e46e02b8e27 100644
--- a/fs/xfs/xfs_bmap_btree.c
+++ b/fs/xfs/xfs_bmap_btree.c
@@ -68,7 +68,7 @@ xfs_bmdr_to_bmbt(
 	struct xfs_mount	*mp,
 	xfs_bmdr_block_t	*dblock,
 	int			dblocklen,
-	xfs_bmbt_block_t	*rblock,
+	struct xfs_btree_block	*rblock,
 	int			rblocklen)
 {
 	int			dmxr;
@@ -81,8 +81,8 @@ xfs_bmdr_to_bmbt(
 	rblock->bb_level = dblock->bb_level;
 	ASSERT(be16_to_cpu(rblock->bb_level) > 0);
 	rblock->bb_numrecs = dblock->bb_numrecs;
-	rblock->bb_leftsib = cpu_to_be64(NULLDFSBNO);
-	rblock->bb_rightsib = cpu_to_be64(NULLDFSBNO);
+	rblock->bb_u.l.bb_leftsib = cpu_to_be64(NULLDFSBNO);
+	rblock->bb_u.l.bb_rightsib = cpu_to_be64(NULLDFSBNO);
 	dmxr = xfs_bmdr_maxrecs(mp, dblocklen, 0);
 	fkp = XFS_BMDR_KEY_ADDR(dblock, 1);
 	tkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
@@ -429,7 +429,7 @@ xfs_bmbt_set_state(
 void
 xfs_bmbt_to_bmdr(
 	struct xfs_mount	*mp,
-	xfs_bmbt_block_t	*rblock,
+	struct xfs_btree_block	*rblock,
 	int			rblocklen,
 	xfs_bmdr_block_t	*dblock,
 	int			dblocklen)
@@ -441,8 +441,8 @@ xfs_bmbt_to_bmdr(
 	__be64			*tpp;
 
 	ASSERT(be32_to_cpu(rblock->bb_magic) == XFS_BMAP_MAGIC);
-	ASSERT(be64_to_cpu(rblock->bb_leftsib) == NULLDFSBNO);
-	ASSERT(be64_to_cpu(rblock->bb_rightsib) == NULLDFSBNO);
+	ASSERT(be64_to_cpu(rblock->bb_u.l.bb_leftsib) == NULLDFSBNO);
+	ASSERT(be64_to_cpu(rblock->bb_u.l.bb_rightsib) == NULLDFSBNO);
 	ASSERT(be16_to_cpu(rblock->bb_level) > 0);
 	dblock->bb_level = rblock->bb_level;
 	dblock->bb_numrecs = rblock->bb_numrecs;
@@ -906,7 +906,7 @@ xfs_bmbt_maxrecs(
 	int			blocklen,
 	int			leaf)
 {
-	blocklen -= sizeof(struct xfs_btree_lblock);
+	blocklen -= XFS_BMBT_BLOCK_LEN(mp);
 
 	if (leaf)
 		return blocklen / sizeof(xfs_bmbt_rec_t);
diff --git a/fs/xfs/xfs_bmap_btree.h b/fs/xfs/xfs_bmap_btree.h
index 7f001072db4..735a42418c9 100644
--- a/fs/xfs/xfs_bmap_btree.h
+++ b/fs/xfs/xfs_bmap_btree.h
@@ -22,7 +22,6 @@
 
 struct xfs_btree_cur;
 struct xfs_btree_block;
-struct xfs_btree_lblock;
 struct xfs_mount;
 struct xfs_inode;
 struct xfs_trans;
@@ -147,27 +146,29 @@ typedef struct xfs_bmbt_key {
 /* btree pointer type */
 typedef __be64 xfs_bmbt_ptr_t, xfs_bmdr_ptr_t;
 
-/* btree block header type */
-typedef struct xfs_btree_lblock xfs_bmbt_block_t;
-
-#define XFS_BUF_TO_BMBT_BLOCK(bp)	((xfs_bmbt_block_t *)XFS_BUF_PTR(bp))
+/*
+ * Btree block header size depends on a superblock flag.
+ *
+ * (not quite yet, but soon)
+ */
+#define XFS_BMBT_BLOCK_LEN(mp)	XFS_BTREE_LBLOCK_LEN
 
 #define XFS_BMBT_REC_ADDR(mp, block, index) \
 	((xfs_bmbt_rec_t *) \
 		((char *)(block) + \
-		 sizeof(struct xfs_btree_lblock) + \
+		 XFS_BMBT_BLOCK_LEN(mp) + \
 		 ((index) - 1) * sizeof(xfs_bmbt_rec_t)))
 
 #define XFS_BMBT_KEY_ADDR(mp, block, index) \
 	((xfs_bmbt_key_t *) \
 		((char *)(block) + \
-		 sizeof(struct xfs_btree_lblock) + \
+		 XFS_BMBT_BLOCK_LEN(mp) + \
 		 ((index) - 1) * sizeof(xfs_bmbt_key_t)))
 
 #define XFS_BMBT_PTR_ADDR(mp, block, index, maxrecs) \
 	((xfs_bmbt_ptr_t *) \
 		((char *)(block) + \
-		 sizeof(struct xfs_btree_lblock) + \
+		 XFS_BMBT_BLOCK_LEN(mp) + \
 		 (maxrecs) * sizeof(xfs_bmbt_key_t) + \
 		 ((index) - 1) * sizeof(xfs_bmbt_ptr_t)))
 
@@ -198,7 +199,7 @@ typedef struct xfs_btree_lblock xfs_bmbt_block_t;
 	XFS_BMBT_PTR_ADDR(mp, bb, i, xfs_bmbt_maxrecs(mp, sz, 0))
 
 #define XFS_BMAP_BROOT_SPACE_CALC(nrecs) \
-	(int)(sizeof(xfs_bmbt_block_t) + \
+	(int)(XFS_BTREE_LBLOCK_LEN + \
 	       ((nrecs) * (sizeof(xfs_bmbt_key_t) + sizeof(xfs_bmbt_ptr_t))))
 
 #define XFS_BMAP_BROOT_SPACE(bb) \
@@ -223,7 +224,7 @@ typedef struct xfs_btree_lblock xfs_bmbt_block_t;
  * Prototypes for xfs_bmap.c to call.
  */
 extern void xfs_bmdr_to_bmbt(struct xfs_mount *, xfs_bmdr_block_t *, int,
-			xfs_bmbt_block_t *, int);
+			struct xfs_btree_block *, int);
 extern void xfs_bmbt_get_all(xfs_bmbt_rec_host_t *r, xfs_bmbt_irec_t *s);
 extern xfs_filblks_t xfs_bmbt_get_blockcount(xfs_bmbt_rec_host_t *r);
 extern xfs_fsblock_t xfs_bmbt_get_startblock(xfs_bmbt_rec_host_t *r);
@@ -246,7 +247,7 @@ extern void xfs_bmbt_disk_set_all(xfs_bmbt_rec_t *r, xfs_bmbt_irec_t *s);
 extern void xfs_bmbt_disk_set_allf(xfs_bmbt_rec_t *r, xfs_fileoff_t o,
 			xfs_fsblock_t b, xfs_filblks_t c, xfs_exntst_t v);
 
-extern void xfs_bmbt_to_bmdr(struct xfs_mount *, xfs_bmbt_block_t *, int,
+extern void xfs_bmbt_to_bmdr(struct xfs_mount *, struct xfs_btree_block *, int,
 			xfs_bmdr_block_t *, int);
 
 extern int xfs_bmbt_get_maxrecs(struct xfs_btree_cur *, int level);
diff --git a/fs/xfs/xfs_btree.c b/fs/xfs/xfs_btree.c
index 72a26bb7643..7ed59267420 100644
--- a/fs/xfs/xfs_btree.c
+++ b/fs/xfs/xfs_btree.c
@@ -53,10 +53,10 @@ const __uint32_t xfs_magics[XFS_BTNUM_MAX] = {
 };
 
 
-int					/* error (0 or EFSCORRUPTED) */
+STATIC int				/* error (0 or EFSCORRUPTED) */
 xfs_btree_check_lblock(
 	struct xfs_btree_cur	*cur,	/* btree cursor */
-	struct xfs_btree_lblock	*block,	/* btree long form block pointer */
+	struct xfs_btree_block	*block,	/* btree long form block pointer */
 	int			level,	/* level of the btree block */
 	struct xfs_buf		*bp)	/* buffer for block, if any */
 {
@@ -69,12 +69,14 @@ xfs_btree_check_lblock(
 		be16_to_cpu(block->bb_level) == level &&
 		be16_to_cpu(block->bb_numrecs) <=
 			cur->bc_ops->get_maxrecs(cur, level) &&
-		block->bb_leftsib &&
-		(be64_to_cpu(block->bb_leftsib) == NULLDFSBNO ||
-		 XFS_FSB_SANITY_CHECK(mp, be64_to_cpu(block->bb_leftsib))) &&
-		block->bb_rightsib &&
-		(be64_to_cpu(block->bb_rightsib) == NULLDFSBNO ||
-		 XFS_FSB_SANITY_CHECK(mp, be64_to_cpu(block->bb_rightsib)));
+		block->bb_u.l.bb_leftsib &&
+		(be64_to_cpu(block->bb_u.l.bb_leftsib) == NULLDFSBNO ||
+		 XFS_FSB_SANITY_CHECK(mp,
+		 	be64_to_cpu(block->bb_u.l.bb_leftsib))) &&
+		block->bb_u.l.bb_rightsib &&
+		(be64_to_cpu(block->bb_u.l.bb_rightsib) == NULLDFSBNO ||
+		 XFS_FSB_SANITY_CHECK(mp,
+		 	be64_to_cpu(block->bb_u.l.bb_rightsib)));
 	if (unlikely(XFS_TEST_ERROR(!lblock_ok, mp,
 			XFS_ERRTAG_BTREE_CHECK_LBLOCK,
 			XFS_RANDOM_BTREE_CHECK_LBLOCK))) {
@@ -90,7 +92,7 @@ xfs_btree_check_lblock(
 STATIC int				/* error (0 or EFSCORRUPTED) */
 xfs_btree_check_sblock(
 	struct xfs_btree_cur	*cur,	/* btree cursor */
-	struct xfs_btree_sblock	*block,	/* btree short form block pointer */
+	struct xfs_btree_block	*block,	/* btree short form block pointer */
 	int			level,	/* level of the btree block */
 	struct xfs_buf		*bp)	/* buffer containing block */
 {
@@ -107,12 +109,12 @@ xfs_btree_check_sblock(
 		be16_to_cpu(block->bb_level) == level &&
 		be16_to_cpu(block->bb_numrecs) <=
 			cur->bc_ops->get_maxrecs(cur, level) &&
-		(be32_to_cpu(block->bb_leftsib) == NULLAGBLOCK ||
-		 be32_to_cpu(block->bb_leftsib) < agflen) &&
-		block->bb_leftsib &&
-		(be32_to_cpu(block->bb_rightsib) == NULLAGBLOCK ||
-		 be32_to_cpu(block->bb_rightsib) < agflen) &&
-		block->bb_rightsib;
+		(be32_to_cpu(block->bb_u.s.bb_leftsib) == NULLAGBLOCK ||
+		 be32_to_cpu(block->bb_u.s.bb_leftsib) < agflen) &&
+		block->bb_u.s.bb_leftsib &&
+		(be32_to_cpu(block->bb_u.s.bb_rightsib) == NULLAGBLOCK ||
+		 be32_to_cpu(block->bb_u.s.bb_rightsib) < agflen) &&
+		block->bb_u.s.bb_rightsib;
 	if (unlikely(XFS_TEST_ERROR(!sblock_ok, cur->bc_mp,
 			XFS_ERRTAG_BTREE_CHECK_SBLOCK,
 			XFS_RANDOM_BTREE_CHECK_SBLOCK))) {
@@ -135,13 +137,10 @@ xfs_btree_check_block(
 	int			level,	/* level of the btree block */
 	struct xfs_buf		*bp)	/* buffer containing block, if any */
 {
-	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
-		return xfs_btree_check_lblock(cur,
-				(struct xfs_btree_lblock *)block, level, bp);
-	} else {
-		return xfs_btree_check_sblock(cur,
-				(struct xfs_btree_sblock *)block, level, bp);
-	}
+	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
+		return xfs_btree_check_lblock(cur, block, level, bp);
+	else
+		return xfs_btree_check_sblock(cur, block, level, bp);
 }
 
 /*
@@ -326,8 +325,8 @@ xfs_btree_dup_cursor(
 static inline size_t xfs_btree_block_len(struct xfs_btree_cur *cur)
 {
 	return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
-		sizeof(struct xfs_btree_lblock) :
-		sizeof(struct xfs_btree_sblock);
+		XFS_BTREE_LBLOCK_LEN :
+		XFS_BTREE_SBLOCK_LEN;
 }
 
 /*
@@ -510,7 +509,7 @@ xfs_btree_islastblock(
 	xfs_btree_cur_t		*cur,	/* btree cursor */
 	int			level)	/* level to check */
 {
-	xfs_btree_block_t	*block;	/* generic btree block pointer */
+	struct xfs_btree_block	*block;	/* generic btree block pointer */
 	xfs_buf_t		*bp;	/* buffer containing block */
 
 	block = xfs_btree_get_block(cur, level, &bp);
@@ -530,7 +529,7 @@ xfs_btree_firstrec(
 	xfs_btree_cur_t		*cur,	/* btree cursor */
 	int			level)	/* level to change */
 {
-	xfs_btree_block_t	*block;	/* generic btree block pointer */
+	struct xfs_btree_block	*block;	/* generic btree block pointer */
 	xfs_buf_t		*bp;	/* buffer containing block */
 
 	/*
@@ -559,7 +558,7 @@ xfs_btree_lastrec(
 	xfs_btree_cur_t		*cur,	/* btree cursor */
 	int			level)	/* level to change */
 {
-	xfs_btree_block_t	*block;	/* generic btree block pointer */
+	struct xfs_btree_block	*block;	/* generic btree block pointer */
 	xfs_buf_t		*bp;	/* buffer containing block */
 
 	/*
@@ -814,7 +813,7 @@ xfs_btree_setbuf(
 	int			lev,	/* level in btree */
 	xfs_buf_t		*bp)	/* new buffer to set */
 {
-	xfs_btree_block_t	*b;	/* btree block */
+	struct xfs_btree_block	*b;	/* btree block */
 	xfs_buf_t		*obp;	/* old buffer pointer */
 
 	obp = cur->bc_bufs[lev];
@@ -1252,20 +1251,20 @@ xfs_btree_log_block(
 	int			first;	/* first byte offset logged */
 	int			last;	/* last byte offset logged */
 	static const short	soffsets[] = {	/* table of offsets (short) */
-		offsetof(struct xfs_btree_sblock, bb_magic),
-		offsetof(struct xfs_btree_sblock, bb_level),
-		offsetof(struct xfs_btree_sblock, bb_numrecs),
-		offsetof(struct xfs_btree_sblock, bb_leftsib),
-		offsetof(struct xfs_btree_sblock, bb_rightsib),
-		sizeof(struct xfs_btree_sblock)
+		offsetof(struct xfs_btree_block, bb_magic),
+		offsetof(struct xfs_btree_block, bb_level),
+		offsetof(struct xfs_btree_block, bb_numrecs),
+		offsetof(struct xfs_btree_block, bb_u.s.bb_leftsib),
+		offsetof(struct xfs_btree_block, bb_u.s.bb_rightsib),
+		XFS_BTREE_SBLOCK_LEN
 	};
 	static const short	loffsets[] = {	/* table of offsets (long) */
-		offsetof(struct xfs_btree_lblock, bb_magic),
-		offsetof(struct xfs_btree_lblock, bb_level),
-		offsetof(struct xfs_btree_lblock, bb_numrecs),
-		offsetof(struct xfs_btree_lblock, bb_leftsib),
-		offsetof(struct xfs_btree_lblock, bb_rightsib),
-		sizeof(struct xfs_btree_lblock)
+		offsetof(struct xfs_btree_block, bb_magic),
+		offsetof(struct xfs_btree_block, bb_level),
+		offsetof(struct xfs_btree_block, bb_numrecs),
+		offsetof(struct xfs_btree_block, bb_u.l.bb_leftsib),
+		offsetof(struct xfs_btree_block, bb_u.l.bb_rightsib),
+		XFS_BTREE_LBLOCK_LEN
 	};
 
 	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
@@ -3018,7 +3017,7 @@ xfs_btree_kill_iroot(
 	if (index) {
 		xfs_iroot_realloc(cur->bc_private.b.ip, index,
 				  cur->bc_private.b.whichfork);
-		block = (struct xfs_btree_block *)ifp->if_broot;
+		block = ifp->if_broot;
 	}
 
 	be16_add_cpu(&block->bb_numrecs, index);
diff --git a/fs/xfs/xfs_btree.h b/fs/xfs/xfs_btree.h
index d6120a74906..789fffdf8b2 100644
--- a/fs/xfs/xfs_btree.h
+++ b/fs/xfs/xfs_btree.h
@@ -39,31 +39,16 @@ extern kmem_zone_t	*xfs_btree_cur_zone;
 #define	XFS_BTNUM_INO	((xfs_btnum_t)XFS_BTNUM_INOi)
 
 /*
- * Short form header: space allocation btrees.
+ * Generic btree header.
+ *
+ * This is a comination of the actual format used on disk for short and long
+ * format btrees.  The first three fields are shared by both format, but
+ * the pointers are different and should be used with care.
+ *
+ * To get the size of the actual short or long form headers please use
+ * the size macros below.  Never use sizeof(xfs_btree_block).
  */
-typedef struct xfs_btree_sblock {
-	__be32		bb_magic;	/* magic number for block type */
-	__be16		bb_level;	/* 0 is a leaf */
-	__be16		bb_numrecs;	/* current # of data records */
-	__be32		bb_leftsib;	/* left sibling block or NULLAGBLOCK */
-	__be32		bb_rightsib;	/* right sibling block or NULLAGBLOCK */
-} xfs_btree_sblock_t;
-
-/*
- * Long form header: bmap btrees.
- */
-typedef struct xfs_btree_lblock {
-	__be32		bb_magic;	/* magic number for block type */
-	__be16		bb_level;	/* 0 is a leaf */
-	__be16		bb_numrecs;	/* current # of data records */
-	__be64		bb_leftsib;	/* left sibling block or NULLDFSBNO */
-	__be64		bb_rightsib;	/* right sibling block or NULLDFSBNO */
-} xfs_btree_lblock_t;
-
-/*
- * Combined header and structure, used by common code.
- */
-typedef struct xfs_btree_block {
+struct xfs_btree_block {
 	__be32		bb_magic;	/* magic number for block type */
 	__be16		bb_level;	/* 0 is a leaf */
 	__be16		bb_numrecs;	/* current # of data records */
@@ -77,7 +62,11 @@ typedef struct xfs_btree_block {
 			__be64		bb_rightsib;
 		} l;			/* long form pointers */
 	} bb_u;				/* rest */
-} xfs_btree_block_t;
+};
+
+#define XFS_BTREE_SBLOCK_LEN	16	/* size of a short form block */
+#define XFS_BTREE_LBLOCK_LEN	24	/* size of a long form block */
+
 
 /*
  * Generic key, ptr and record wrapper structures.
@@ -294,21 +283,9 @@ typedef struct xfs_btree_cur
 /*
  * Convert from buffer to btree block header.
  */
-#define	XFS_BUF_TO_BLOCK(bp)	((xfs_btree_block_t *)XFS_BUF_PTR(bp))
-#define	XFS_BUF_TO_LBLOCK(bp)	((xfs_btree_lblock_t *)XFS_BUF_PTR(bp))
-#define	XFS_BUF_TO_SBLOCK(bp)	((xfs_btree_sblock_t *)XFS_BUF_PTR(bp))
+#define	XFS_BUF_TO_BLOCK(bp)	((struct xfs_btree_block *)XFS_BUF_PTR(bp))
 
 
-/*
- * Check that long form block header is ok.
- */
-int					/* error (0 or EFSCORRUPTED) */
-xfs_btree_check_lblock(
-	struct xfs_btree_cur	*cur,	/* btree cursor */
-	struct xfs_btree_lblock	*block,	/* btree long form block pointer */
-	int			level,	/* level of the btree block */
-	struct xfs_buf		*bp);	/* buffer containing block, if any */
-
 /*
  * Check that block header is ok.
  */
diff --git a/fs/xfs/xfs_dinode.h b/fs/xfs/xfs_dinode.h
index 2a00fcc36d8..d7cf392cc85 100644
--- a/fs/xfs/xfs_dinode.h
+++ b/fs/xfs/xfs_dinode.h
@@ -165,7 +165,7 @@ typedef enum xfs_dinode_fmt
  */
 #define	XFS_LITINO(mp)	((mp)->m_litino)
 #define	XFS_BROOT_SIZE_ADJ	\
-	(sizeof(xfs_bmbt_block_t) - sizeof(xfs_bmdr_block_t))
+	(XFS_BTREE_LBLOCK_LEN - sizeof(xfs_bmdr_block_t))
 
 /*
  * Inode data & attribute fork sizes, per inode.
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 8ce72aba027..f1d0585041b 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -126,7 +126,7 @@ xfs_growfs_data_private(
 	xfs_extlen_t		agsize;
 	xfs_extlen_t		tmpsize;
 	xfs_alloc_rec_t		*arec;
-	xfs_btree_sblock_t	*block;
+	struct xfs_btree_block	*block;
 	xfs_buf_t		*bp;
 	int			bucket;
 	int			dpct;
@@ -251,13 +251,13 @@ xfs_growfs_data_private(
 		bp = xfs_buf_get(mp->m_ddev_targp,
 			XFS_AGB_TO_DADDR(mp, agno, XFS_BNO_BLOCK(mp)),
 			BTOBB(mp->m_sb.sb_blocksize), 0);
-		block = XFS_BUF_TO_SBLOCK(bp);
+		block = XFS_BUF_TO_BLOCK(bp);
 		memset(block, 0, mp->m_sb.sb_blocksize);
 		block->bb_magic = cpu_to_be32(XFS_ABTB_MAGIC);
 		block->bb_level = 0;
 		block->bb_numrecs = cpu_to_be16(1);
-		block->bb_leftsib = cpu_to_be32(NULLAGBLOCK);
-		block->bb_rightsib = cpu_to_be32(NULLAGBLOCK);
+		block->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
+		block->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
 		arec = XFS_ALLOC_REC_ADDR(mp, block, 1);
 		arec->ar_startblock = cpu_to_be32(XFS_PREALLOC_BLOCKS(mp));
 		arec->ar_blockcount = cpu_to_be32(
@@ -272,13 +272,13 @@ xfs_growfs_data_private(
 		bp = xfs_buf_get(mp->m_ddev_targp,
 			XFS_AGB_TO_DADDR(mp, agno, XFS_CNT_BLOCK(mp)),
 			BTOBB(mp->m_sb.sb_blocksize), 0);
-		block = XFS_BUF_TO_SBLOCK(bp);
+		block = XFS_BUF_TO_BLOCK(bp);
 		memset(block, 0, mp->m_sb.sb_blocksize);
 		block->bb_magic = cpu_to_be32(XFS_ABTC_MAGIC);
 		block->bb_level = 0;
 		block->bb_numrecs = cpu_to_be16(1);
-		block->bb_leftsib = cpu_to_be32(NULLAGBLOCK);
-		block->bb_rightsib = cpu_to_be32(NULLAGBLOCK);
+		block->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
+		block->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
 		arec = XFS_ALLOC_REC_ADDR(mp, block, 1);
 		arec->ar_startblock = cpu_to_be32(XFS_PREALLOC_BLOCKS(mp));
 		arec->ar_blockcount = cpu_to_be32(
@@ -294,13 +294,13 @@ xfs_growfs_data_private(
 		bp = xfs_buf_get(mp->m_ddev_targp,
 			XFS_AGB_TO_DADDR(mp, agno, XFS_IBT_BLOCK(mp)),
 			BTOBB(mp->m_sb.sb_blocksize), 0);
-		block = XFS_BUF_TO_SBLOCK(bp);
+		block = XFS_BUF_TO_BLOCK(bp);
 		memset(block, 0, mp->m_sb.sb_blocksize);
 		block->bb_magic = cpu_to_be32(XFS_IBT_MAGIC);
 		block->bb_level = 0;
 		block->bb_numrecs = 0;
-		block->bb_leftsib = cpu_to_be32(NULLAGBLOCK);
-		block->bb_rightsib = cpu_to_be32(NULLAGBLOCK);
+		block->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
+		block->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
 		error = xfs_bwrite(mp, bp);
 		if (error) {
 			goto error0;
diff --git a/fs/xfs/xfs_ialloc_btree.c b/fs/xfs/xfs_ialloc_btree.c
index 46aabb3fcbf..99f2408e8d8 100644
--- a/fs/xfs/xfs_ialloc_btree.c
+++ b/fs/xfs/xfs_ialloc_btree.c
@@ -375,7 +375,7 @@ xfs_inobt_maxrecs(
 	int			blocklen,
 	int			leaf)
 {
-	blocklen -= sizeof(struct xfs_btree_sblock);
+	blocklen -= XFS_INOBT_BLOCK_LEN(mp);
 
 	if (leaf)
 		return blocklen / sizeof(xfs_inobt_rec_t);
diff --git a/fs/xfs/xfs_ialloc_btree.h b/fs/xfs/xfs_ialloc_btree.h
index fa12c85db34..37e5dd01a57 100644
--- a/fs/xfs/xfs_ialloc_btree.h
+++ b/fs/xfs/xfs_ialloc_btree.h
@@ -24,7 +24,6 @@
 
 struct xfs_buf;
 struct xfs_btree_cur;
-struct xfs_btree_sblock;
 struct xfs_mount;
 
 /*
@@ -70,11 +69,6 @@ typedef struct xfs_inobt_key {
 /* btree pointer type */
 typedef __be32 xfs_inobt_ptr_t;
 
-/* btree block header type */
-typedef	struct xfs_btree_sblock xfs_inobt_block_t;
-
-#define	XFS_BUF_TO_INOBT_BLOCK(bp)	((xfs_inobt_block_t *)XFS_BUF_PTR(bp))
-
 /*
  * Bit manipulations for ir_free.
  */
@@ -95,6 +89,13 @@ typedef	struct xfs_btree_sblock xfs_inobt_block_t;
 #define	XFS_IBT_BLOCK(mp)		((xfs_agblock_t)(XFS_CNT_BLOCK(mp) + 1))
 #define	XFS_PREALLOC_BLOCKS(mp)		((xfs_agblock_t)(XFS_IBT_BLOCK(mp) + 1))
 
+/*
+ * Btree block header size depends on a superblock flag.
+ *
+ * (not quite yet, but soon)
+ */
+#define XFS_INOBT_BLOCK_LEN(mp)	XFS_BTREE_SBLOCK_LEN
+
 /*
  * Record, key, and pointer address macros for btree blocks.
  *
@@ -103,19 +104,19 @@ typedef	struct xfs_btree_sblock xfs_inobt_block_t;
 #define XFS_INOBT_REC_ADDR(mp, block, index) \
 	((xfs_inobt_rec_t *) \
 		((char *)(block) + \
-		 sizeof(struct xfs_btree_sblock) + \
+		 XFS_INOBT_BLOCK_LEN(mp) + \
 		 (((index) - 1) * sizeof(xfs_inobt_rec_t))))
 
 #define XFS_INOBT_KEY_ADDR(mp, block, index) \
 	((xfs_inobt_key_t *) \
 		((char *)(block) + \
-		 sizeof(struct xfs_btree_sblock) + \
+		 XFS_INOBT_BLOCK_LEN(mp) + \
 		 ((index) - 1) * sizeof(xfs_inobt_key_t)))
 
 #define XFS_INOBT_PTR_ADDR(mp, block, index, maxrecs) \
 	((xfs_inobt_ptr_t *) \
 		((char *)(block) + \
-		 sizeof(struct xfs_btree_sblock) + \
+		 XFS_INOBT_BLOCK_LEN(mp) + \
 		 (maxrecs) * sizeof(xfs_inobt_key_t) + \
 		 ((index) - 1) * sizeof(xfs_inobt_ptr_t)))
 
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 7b4f13c710d..bc33762abc4 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2352,7 +2352,7 @@ xfs_iroot_realloc(
 	struct xfs_mount	*mp = ip->i_mount;
 	int			cur_max;
 	xfs_ifork_t		*ifp;
-	xfs_bmbt_block_t	*new_broot;
+	struct xfs_btree_block	*new_broot;
 	int			new_max;
 	size_t			new_size;
 	char			*np;
@@ -2373,8 +2373,7 @@ xfs_iroot_realloc(
 		 */
 		if (ifp->if_broot_bytes == 0) {
 			new_size = (size_t)XFS_BMAP_BROOT_SPACE_CALC(rec_diff);
-			ifp->if_broot = (xfs_bmbt_block_t*)kmem_alloc(new_size,
-								     KM_SLEEP);
+			ifp->if_broot = kmem_alloc(new_size, KM_SLEEP);
 			ifp->if_broot_bytes = (int)new_size;
 			return;
 		}
@@ -2388,9 +2387,7 @@ xfs_iroot_realloc(
 		cur_max = xfs_bmbt_maxrecs(mp, ifp->if_broot_bytes, 0);
 		new_max = cur_max + rec_diff;
 		new_size = (size_t)XFS_BMAP_BROOT_SPACE_CALC(new_max);
-		ifp->if_broot = (xfs_bmbt_block_t *)
-		  kmem_realloc(ifp->if_broot,
-				new_size,
+		ifp->if_broot = kmem_realloc(ifp->if_broot, new_size,
 				(size_t)XFS_BMAP_BROOT_SPACE_CALC(cur_max), /* old size */
 				KM_SLEEP);
 		op = (char *)XFS_BMAP_BROOT_PTR_ADDR(mp, ifp->if_broot, 1,
@@ -2418,11 +2415,11 @@ xfs_iroot_realloc(
 	else
 		new_size = 0;
 	if (new_size > 0) {
-		new_broot = (xfs_bmbt_block_t *)kmem_alloc(new_size, KM_SLEEP);
+		new_broot = kmem_alloc(new_size, KM_SLEEP);
 		/*
 		 * First copy over the btree block header.
 		 */
-		memcpy(new_broot, ifp->if_broot, sizeof(xfs_bmbt_block_t));
+		memcpy(new_broot, ifp->if_broot, XFS_BTREE_LBLOCK_LEN);
 	} else {
 		new_broot = NULL;
 		ifp->if_flags &= ~XFS_IFBROOT;
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 55d50b888b6..6fd20fc179a 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -63,7 +63,7 @@ typedef struct xfs_ext_irec {
 typedef struct xfs_ifork {
 	int			if_bytes;	/* bytes in if_u1 */
 	int			if_real_bytes;	/* bytes allocated in if_u1 */
-	xfs_bmbt_block_t	*if_broot;	/* file's incore btree root */
+	struct xfs_btree_block	*if_broot;	/* file's incore btree root */
 	short			if_broot_bytes;	/* bytes allocated for root */
 	unsigned char		if_flags;	/* per-fork flags */
 	unsigned char		if_ext_max;	/* max # of extent records */
@@ -213,7 +213,6 @@ struct ktrace;
 struct xfs_buf;
 struct xfs_bmap_free;
 struct xfs_bmbt_irec;
-struct xfs_bmbt_block;
 struct xfs_inode_log_item;
 struct xfs_mount;
 struct xfs_trans;
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 23c3a782a9e..199c8ea3647 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -2452,8 +2452,8 @@ xlog_recover_do_inode_trans(
 		break;
 
 	case XFS_ILOG_DBROOT:
-		xfs_bmbt_to_bmdr(mp, (xfs_bmbt_block_t *)src, len,
-				 &(dip->di_u.di_bmbt),
+		xfs_bmbt_to_bmdr(mp, (struct xfs_btree_block *)src, len,
+				 &dip->di_u.di_bmbt,
 				 XFS_DFORK_DSIZE(dip, mp));
 		break;
 
@@ -2490,8 +2490,8 @@ xlog_recover_do_inode_trans(
 
 		case XFS_ILOG_ABROOT:
 			dest = XFS_DFORK_APTR(dip);
-			xfs_bmbt_to_bmdr(mp, (xfs_bmbt_block_t *)src, len,
-					 (xfs_bmdr_block_t*)dest,
+			xfs_bmbt_to_bmdr(mp, (struct xfs_btree_block *)src,
+					 len, (xfs_bmdr_block_t*)dest,
 					 XFS_DFORK_ASIZE(dip, mp));
 			break;